| The crux of maintaining the apple industry developing steadily and healthily is to enhance its benefit keeping pace with the increasing of apple quantity and the development of apple industry.New apple products development is an important way to raise the benefit. Now that the products of acetic acid fermentation have good market vista, the bases to stabilize and develop the market are the application of advanced techniques and the enhancement of its quality.Beginning with the application of apples to the production of apple acetic acid fermentation products, in the ways of basic microbial techniques, advanced fermentation and analysis techniques, the research works of apple vinegar brewing techniques and measures of enhancing acidification ability and flavor quality have been conducted.Because alcohol fermentation is the precondition for apple vinegar production,alcohol produced by using Fruit-Grain mixed fermentation was studied first.Wine Yeast D1 was selected as the starting yeast.It was determined that the optimum proportion of fruit-grain was 1:1 and primary total sugar was 13%. The optimum alcohol fermentation conditions were optimized by single factor test and by SAS software combined with the Plackett-Burman design and Response surface analysis method. Approp- riate Urea and Ammonium sulfate addition could advance the alcohol production .MgSO4 and KH2PO4 addition also could advance the alcohol production .The optimal addition was that (NH4)2SO4 0.15%;KH2PO4 0.05% and MgSO4 0.1%.The ultimate alcohol concentration was 7.8% and the fermentation cycle was 108h.Two strains of acetic bacteria were screened from vinegar grains and rotten apple,named DT-2 and AD1.Results of strain identification showed that the strain DT-2 was Ace.ascendens and the strain AD1 was Ace. Subxydans. The optimalfermentation conditions were optimized by single factor test and by SAS software combined with the Plackett-Burman design and Response surface analysis method.Then this research studied the brewing of apple vinegar by strain DT-2,using the alcohol from fermentation.The fermented broth containing some sugar benefited acidification,but higher sugar concentration can restrain acetic acid fermentation. Higher alcohol concentration can res- train acetic acid fermentation too.While the alcohol concentration was 6% and the sugar concentration was 0.8%,the acetic acid concentration was 5.36% and the acidification yield from alcohol was highest.Acetic acid addition can advance acidification and the optimal addition concentration was 0.5%～1.5%.Apple vinegar produced in 5L fermentor was also studied.The ultimate alcohol concentration was 7.08% in the fruit-grain mixed fermentation,and the fermentation cycle was 36h.The ultimate total acid concentration was 5.63% in vinegar fermentation,and the fermentation cycle was 72h.Furthermore pure apple juice for alcohol fermentation was studied,the ultimate alcohol concentration was 6.55%,and the fermentation cycle was 4 days.As for apple vinegar beverage production by the strain AD1,While the alcohol concentration was adjused to 3% in the fermentation broth,the ultimate acid concentration was 2.67%,and the fermentation cycle was 7 days.Adding cane sugar,citric and calcium lactate can remarkably eliminate the irritate taste of apple vinegar beverage.The optimal recipe of apple vinegar beverage determined by single factor test and orthogonal test was:apple vinegar beverage 100mL,cane sugar 12g,citric acid 100mg and calcium lactate 150mg.Finally this research showed the fermentation by two strains DT-2 and AD1 was beneficial to advance the flavor and nutrition of the apple vinegar.The optimal conditions were: the strains proportion DT-2 to AD1 3:2,the inoculate volume 7%,the inoculate sequence inoculating the strain DT-2,12h later inoculating the strain AD1.The ultimate total acid concentration was 4.70%,and the fermentation cycle was 5 days.
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